import java.util.Scanner;

class ZuHeShu{
    int zuheshu (int n,int m){
        if(m==1) return n;
        else if(m==0) return 1;
        else if(m==n) return 1;
        else if (n>m&&m>1&&n>1) return zuheshu(n-1,m-1)+zuheshu(n-1,m);
        else      return -1;
    }
}

public class diedai {
    public static void main(String[] args) {
        Scanner reader = new Scanner (System.in);
        System.out.println("输入m:");
        int m=reader.nextInt();

        System.out.println("输入n:");
        int n=reader.nextInt();

        ZuHeShu a =new ZuHeShu();

        if(a.zuheshu(n,m)==-1)
            System.out.println("输入数据有误");

        else
            System.out.println("C(n,m)="+a.zuheshu(n,m));
    }
}
